Dynamic response and failure process of horizontal-layered fractured structure rock slope under strong earthquake

Rock slope with horizontal-layered fractured structure (HLFS) has high stability in its natural state. However, a strong earthquake can induce rock fissure expansion, ultimately leading to slope failure. In this study, the dynamic response, failure mode, and spectral characteristics of rock slope with HLFS under strong earthquake conditions were investigated based on the large-scale shaking table model test. On this basis, multiple sets of numerical calculation models were further established by UDEC discrete element program. Five influencing factors were considered in the parametric study of numerical simulations, including slope height, slope angle, bedding-plane spacing and secondary joint spacing as well as bedrock dip angle. The results showed that the failure process of rock slope with HLFS under earthquake action is mainly divided into four phases, i.e., the tensile crack of the slope shoulder joints and shear dislocation at the top bedding plane, the extension of vertical joint cracks and increase of shear displacement, the formation of step-through sliding surfaces and the instability, and finally collapse of fractured rock mass. The acceleration response of slopes exhibits elevation amplification effect and surface effect. Numerical simulations indicate that the seismic stability of slopes with HLFS exhibits a negative correlation with slope height and angle, but a positive correlation with bedding-plane spacing, joint spacing, and bedrock dip angle. The results of this study can provide a reference for seismic stability evaluation of weathered rock slopes.